Nozzle for teeming vessel



1958 E. A. NIRMAIER ET AL NOZZLE FOR TEEMING VESSEL Filed Oct. 20. 1955Els "1.

BY. Adam 04225271 their Attorney.

United NOZZLE FOR TEEMING VESSEL Application October 20, 1955, SerialNo. 541,610

3 Claims. 01. 22-85) This invention relates to a nozzle havingimprovements directed to the end of streamlining the flow of fluidtherethrough and, more particularly, to a teeming nozzle forstreamlining the flow of molten metal from a refractory lined metalladle into an ingot mold.

In the casting of metal ingots, splashing of molten metal being teemedinto a mold causes ingot surface defects, the more common of which arescabs, folds and non-metallic inclusions. The molten metal is of courseteemed into the ingot mold through a teeming orifice extendingvertically and centrally of a nozzle mounted in the bottom of a ladle.In order to reduce splashing and the resulting ingot surface defects, itis desirable to have the metal fiow from the nozzle orifice with aslittle turbulence and spraying as possible. For this purpose, theconventional practice has been to construct teeming nozzles with alength several times the orifice diameter in order to obtain astreamline flow of the teeming metal. However, this practice has notproved entirely effective and the problem of splashing in the casting ofmetal ingots continues to be troublesome.

One of the principal objects of the invention is to provide an improvedteeming nozzle which will be effective under different pouringconditions to streamline the flow of metal from the ladle into an ingotmold.

Another object of the invention is to eliminate cavitation of a streamof metal during teeming movement through a teeming nozzle orifice.

A further object of the invention is to provide a teeming nozzle formetal ladles with a passageway for venting its orifice to the atmosphereor other suitable gaseous medium.

A still further object of the invention is to provide a vented nozzle ofthe character just referred to in which the venting passageway opensinto the nozzle orifice at a point adjacent the intersection of theconical well and cylindrical bore which cooperate to form the nozzleorifice. In the preferred embodiment of the invention, the ventingpassageway opens in a manner to be described into the nozzle orifice atthe upper end of its cylindrical bore and just below its intersectionwith the conical well at the upper end of the nozzle.

Other objects and advantages of the invention will become apparent fromthe following description.

In the drawings, there is shown a preferred embodiment of the invention.In this showing:

Figure l is a fragmentary sectional view of a teeming ladle having anozzle constructed in accordance with the principles of this invention;and

Figure 2 is an enlarged sectional view of the nozzle taken along theline IIlI of Figure 1.

In the drawings, the numeral 1 designates the metal shell of a teemingladle which has a lining 2 of refractory material. A teeming nozzle 3comprising a refractory body is mounted at the bottom of the ladle in aposition concentrically of aligned openings through the lining 2 andshell 1. The nozzle opening in the refractory 2 has a steppedconfiguration providing an enlargement 4 tates Patent the size of theingot to be cast.

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in which a rammed well 5 of refractory material is re ceived to mountthe nozzle in position. The well 5 has an upwardly facing conical recess6 forming a continuation of the surface of a conical well or depression7 in the upper end of the nozzle 3. The nozzle 3 has a centrally locatedcylindrical bore 8 which intersects with the conical well 7 and definesa circle 9 at its point of intersection therewith. The conical well 7and cylindrical bore 8 depending therefrom cooperate to provide ateeming orifice 10 through the nozzle 3. A stopper rod 11 has seatingengagement at its lower end against the conical well 7 for stopping theflow of metal through the orifice 10. The ladle construction thus fardescribed is conventional.

The size of the nozzle 3 and the diameter of its cylindrical bore 8 ingeneral vary with the grade of steel and As indicated above, theconventional practice has been to construct nozzles 3 having a lengthsuch that the axial length of the bore 8 is several times the orificediameter for the purpose of obtaining a streamline flow of metaltherethrough with as little turbulence and spraying as possible.However, such constructions have not been entirely effective ineliminating turbulence and spraying of the metal being teemed.

We have found that the flow characteristics of a liquid moving through anozzle orifice 10 of the configuration shown in the drawings varies withthe pressure head of the liquid in the vessel and with its velocity offlow through the bore 8. Generally stated, a streamline flow occurs atlow pressure heads and velocities and the flow becomes turbulent as thepressure head and velocity increase. The turbulent condition of flowcontinues until the pressure head and velocity increase further to apoint at which the fiow abruptly reverts to a streamlined condition.During the intermediate regions of pressure heads and velocities givingrise to a turbulent flow, further investigations have shown thatcavitation of the stream of liquid flowing through the orifice 10 takesplace in a small annular area 12 at the upper end of the bore 8 andadjacent the circle 9. For purposes of illustration, this annular area12 may be considered as extending between the circle 9 and dotted line13. Pressure measurements have shown that a negative pressure of up toas much as 28 inches of mercury is produced in the annular area 12 atthe surface of the bore 8 under turbulent conditions of flow. Thisnegative pressure is a minimum when the flow initially becomes turbulentand increases as the flow becomes more turbulent under increasedpressure heads and velocities.

In accordance with the principles of this invention, a streamline flowthrough the orifice 10 is obtained under all conditions of pressureheads and velocities by venting the area 12 to the atmosphere or othergaseous medium at atmospheric or above pressure. This is accomplished bydrilling the nozzle 3 to provide a radially extending opening 14 whichopens through the wall of the bore 8 into the orifice It) in the annulararea 12 thereof. A vertically extending opening 15 is bored in thenozzle 3 and has its upper end connected with the opening 14- and itslower end open to the atmosphere. If desired, the lower end of theopening 14 may be connected to a source of other suitable gas at apressure approximating that of the atmosphere. With the area 12 ventedin this manner by the openings 14 and 15, a streamline flow of liquidthrough the orifice 10, and particularly through the portion thereofprovided by the bore 8, is had under all pressure heads and velocitieswhich would otherwise be effective to cause a turbulent flow. Inaddition to eliminating turbulence, it will be apparent that the ventingaction provided by the openings 14 and 15 enables the use of nozzles 3having a shorter axial length than 3. heretoforev considered.essentialaccording to conventional practice. Although the drawings showonly a single venting opening 14, it will be understood that in actualpractice a nozzle 3 will. be provided with several such openings sothatclos'ing of. one or more WillvnOt inter fere with venting to theatmosphere as described.

While the above description and the showing in the drawings are specificto the use of the nozzle 3 in teeming molten metal from a ladle into aningot, it will be understood that the disclosure in this respectrepresents a preferred embodiment and application of the invention.Accordingly, it will be further understood that a nozzle having a ventopening into the area 12 has general application to the end of obtaininga streamline flow of other fluids and that other adaptations andmodifications are contemplated and may be made without departing fromthe scope of the following claims.

We claim:

1. In a refractory lined metal ladle having a teeming opening in thebottom thereof the combination with said ladle of, a nozzle comprising arefractory body mounted in said opening, said body having a conical wellin the upper end thereof, a vertically extending cylindrical boreintersecting with said well and cooperating therewith to provide ateeming orifice arranged concentrically'of said ladle opening, and avent opening into said orifice at a point below and adjacent theintersection of said conical well and cylindrical bore and connectingsaid orifice to the atmosphere.

2. In a refractory lined metal ladle having a teeming opening in thebottom thereof the combination with said ladle of, a nozzle comprising arefractory body mounted in said opening, said body having a conical wellin the upper end thereof, a vertically extending cylindrical boreintersecting with said well and cooperating therewith to provide ateeming orifice arranged concentrically of said ladle opening, and avent comprising a first passageway extending radially through the wallof said bore and opening into said orifice at a point below and adjacentthe intersection of said bore and well, and a second passagewayextending axially through the wall of said bore and having its upper endintersecting with said first passageway and its lower end open to theatmosphere.

3. A method of obtaining a streamline fiow of fluid through a dischargeorifice in the bottom of a receptacle in which the discharge orifice isdefined by a vertically extending nozzle body having a conical well inthe upper end thereof and a cylindrical bore intersecting with andextending downwardly from said well, which comprises the step of ventingsaid orifice to the atmosphere at a point in an annular area adjacentand immediately below the said intersection of saidbore and Well, tothereby prevent negative pressures in said annular area and cavitationof a fiuid stream flowing through said orifice.

References Cited in the file of this patent UNITED STATES PATENTS1,090,044 Fuss Mar. 10, 1914 1,261,509 Getman Apr. 2, 1918 2,215,132Parker Sept. 17, 1940 2,348,199 Freeman May 9, 1944 2,705,622 Laub Apr.5, 1955 FOREIGN PATENTS 808,711 France Nov. 24, 1936

